WO2020044529A1

WO2020044529A1 - Method for manufacturing resin molded product

Info

Publication number: WO2020044529A1
Application number: PCT/JP2018/032322
Authority: WO
Inventors: 雅憲森本; 正彦今泉; 功康中島; 浅地　正博; 憲次石井; 遼山崎
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2018-08-31
Filing date: 2018-08-31
Publication date: 2020-03-05

Abstract

The purpose of the present disclosure is to reliably form a desired texture on the inner surface of a hollow resin molded product. The present disclosure is a method for manufacturing a resin molded product in which a resin molded product (drain pipe 10) having a hollow portion (flow path 11) is molded by joining a first divided body 21 and a second divided body 22. The manufacturing method includes a molding step for molding the first divided body and the second divided body by primary injecting a resin material into a space (cavities 210, 220) formed by a first mold 400 and a second mold 500, a moving step for bringing the first divided body and the second divided body closer to each other by the relative movement of the first mold and the second mold, and a joining step of joining the first divided body and the second divided body. A texture forming part for molding a texture on the inner surface of the hollow portion is provided on at least one of the region of the first mold corresponding to the second divided body in the molding step and the region of the second mold corresponding to the first divided body in the molding step.

Description

Method for manufacturing resin molded products

The present invention relates to a method for producing a hollow resin molded product such as a drain pipe.

For example, as a hollow resin molded product such as a drain pipe, a molded product formed by blow molding is known (for example, see Patent Document 1).

By the way, in the drain pipe, formation of a desired texture (texture, roughness, unevenness, etc.) on the inner surface of the flow channel in order to control the flow of the drain is being studied. However, if the drain pipe is formed by blow molding, forming a desired texture on the inner surface of the flow path involves executing a process dedicated to texture formation after blow molding, and the entire manufacturing process becomes longer. Also, depending on the shape of the drain pipe, it may be difficult to form a desired texture on the inner surface of the flow channel after blow molding.

JP 2007-138498 A

Therefore, an object of the present invention is to provide a method of manufacturing a resin molded product that can reliably form a desired texture on the inner surface of a hollow resin molded product without executing a process dedicated to texture formation. .

In order to achieve the above object, a method of manufacturing a resin molded product according to one embodiment of the present invention is a method of forming a resin molded product having a hollow portion by joining a first divided body and a second divided body. A method of manufacturing an article, wherein a resin material is primarily injected into a space formed by a first mold and a second mold to individually mold the first divided body and the second divided body; With the first divided body held by the first mold and the second divided body held by the second mold, the first divided body and the second divided body are moved by relative movement of the first mold and the second mold. A moving step of bringing the joining edges of the divided body closer to each other and a joining step of joining the joining edges of the first divided body and the second divided body to each other; A region corresponding to the second divided body and a first divided body in the molding step in the second mold. At least one of the frequency, the texture forming unit for forming the texture of the inner surface of the resin molded article is provided.

FIG. 1 is a front view showing a schematic configuration of a drain pipe according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view of the above drain pipe. FIG. 3 is an enlarged cross-sectional view showing the inner surface shapes of a first divided body and a second divided body of the drain pipe according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the mold according to the first embodiment, which is opened. FIG. 5 is a cross-sectional view of the above-described mold, showing a state where the mold is closed during primary injection. FIG. 6 is an enlarged cross-sectional view showing a region where the internal shape of the first divided body is formed in the first core portion according to the first embodiment. FIG. 7 is a cross-sectional view illustrating a state of a mold during a molding process according to the first embodiment. FIG. 8 is a cross-sectional view illustrating a state of the mold during the moving process according to the first embodiment. FIG. 9 is a cross-sectional view illustrating a state of the mold at the time of the joining step according to the first embodiment. FIG. 10 is a sectional view of a drain pipe according to the second embodiment. FIG. 11 is an enlarged cross-sectional view showing a part of a drainage pipe before a secondary injection according to the second embodiment. FIG. 12 is an enlarged cross-sectional view showing a part of the drainage pipe before the secondary injection according to the second embodiment. FIG. 13 is a cross-sectional view of the first divided body and the second divided body during the moving process according to the third embodiment. FIG. 14 is a cross-sectional view of the first divided body and the second divided body before the secondary injection after the moving process according to the third embodiment. FIG. 15 is an enlarged cross-sectional view showing a part of the first divided body and the second divided body before the secondary injection after the moving process according to the third embodiment. FIG. 16 is an enlarged cross-sectional view showing a part of the first divided body, the second divided body, and the resin material after the secondary injection in the joining step according to the third embodiment. FIG. 17 is an enlarged cross-sectional view showing a part of the first divided body, the second divided body, and the resin material after the secondary injection in the bonding step according to the comparative example. FIG. 18 is a sectional view of a drain pipe according to the fourth embodiment.

Hereinafter, a method for manufacturing a resin molded product according to an embodiment of the present invention will be described in detail with reference to the drawings. It should be noted that each of the embodiments described below shows a preferred specific example of the present invention. Therefore, the numerical values, shapes, materials, constituent elements, arrangement and connection forms of constituent elements, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. Therefore, among the components in the following embodiments, components that are not described in independent claims that indicate the highest concept of the present invention are described as arbitrary components.

図 Moreover, each drawing is a schematic diagram and is not necessarily strictly illustrated. In each drawing, the same components are denoted by the same reference numerals.

(First embodiment)
Hereinafter, a method for manufacturing a resin molded product according to the first embodiment will be described with reference to FIGS.

[Resin molded products]
First, an example of a resin molded product molded by the method for producing a resin molded product according to the first embodiment will be described. Here, a resin drainage pipe will be described as an example of the resin molded product. The resin molded product is not limited to a drain pipe, and may be any resin molded product having a hollow portion.

FIG. 1 is a front view showing a schematic configuration of a drain pipe according to the first embodiment. FIG. 2 is a sectional view of a drain pipe according to the first embodiment. Specifically, FIG. 2 is a cross-sectional view as viewed from the II-II cross section in FIG.

排水 As shown in FIGS. 1 and 2, the drainage pipe 10 is, for example, an S-shaped trap having an S-shaped flow path 11 as a hollow portion. Here, an S-shaped trap will be described as an example of the drain pipe 10, but a P-shaped drain pipe other than the S-trap may be used.

The drain pipe 10 has an inlet 12 formed at an upper part, an outlet 13 formed at a lower part, and an S-shaped flow path 11 formed to communicate the inlet 12 and the outlet 13. . The drain pipe 10 is integrally formed of a resin material, but is divided into a first divided body 21 and a second divided body 22 at the time of manufacture. By joining the second divided body 22 at the joining portion 23, the entire drain pipe 10 is integrated.

The first divided body 21 is a part that forms the upper half of the drain pipe 10 in FIG. The first divided body 21 is formed with a first groove 211 having an S-shape as viewed from the front, which forms the flow path 11. A concave portion 213 is formed at a joining edge 212 of the first divided body 21 with the second divided body 22. The concave portion 213 is formed along the outer surface of the first divided body 21, and the joining portion 23 is provided in the concave portion 213.

The second divided body 22 is a part that forms the lower half of the drain pipe 10 in FIG. The second divided body 22 is formed with a second groove 221 having an S-shape in a front view, which forms the flow path 11. A concave portion 223 is formed at a joining edge 222 of the second divided body 22 with the first divided body 21. The concave portion 223 is formed along the outer surface of the second divided body 22, and the joint portion 23 is provided in the concave portion 223.

流路 By joining the first divided body 21 and the second divided body 22, the first groove 211 and the second groove 221 constitute the flow path 11. The flow channel 11 has a first straight portion 111, a second straight portion 112, a third straight portion 113, a first bent portion 114, and a second bent portion 115. The first straight portion 111, the second straight portion 112, and the third straight portion 113 are arranged in parallel. The first bent portion 114 and the second bent portion 115 are bent in a U-shape.

Hereinafter, the description will be made with the upstream side as the base end and the downstream side as the front end with reference to the flow of drainage passing through the drainage pipe 10. The base end of the first straight part 111 is continuous with the inlet 12. The distal end of the first straight portion 111 and the proximal end of the first bent portion 114 are continuous. The distal end of the first bent portion 114 and the proximal end of the second straight portion 112 are continuous. The distal end of the second straight portion 112 and the proximal end of the second bent portion 115 are continuous. The distal end of the second bent portion 115 and the proximal end of the third straight portion 113 are continuous. The tip of the third straight portion 113 is continuous with the outlet 13.

In the first divided body 21 and the second divided body 22,

first gaps

24 and 25 are formed between outer walls of the first straight part 111 and the second straight part 112 which are opposed by the first bent part 114. Have been. In the first divided body 21 and the second divided body 22,

second gaps

26 and 27 are formed between the outer walls of the second straight portion 112 and the third straight portion 113 which are opposed by the second bent portion 115. Have been. Joints 23 are provided in the

first gaps

24 and 25 and the

second gaps

26 and 27, respectively.

The joint 23 is a portion that fills the

recesses

213 and 223 and joins the first divided body 21 and the second divided body 22. The portion of the joint 23 corresponding to the

first gaps

24, 25 and the

second gaps

26, 27 is a rib 231 protruding from one of the opposed outer walls toward the other. Specifically, the rib 231 is connected to outer walls of the first divided body 21 and the second divided body 22. The rib 231 may be separated from one of the opposing outer walls or the other. FIG. 1 shows a case where the rib 231 is formed continuously along the longitudinal direction of each of the

first gaps

24 and 25 and the

second gaps

26 and 27, but is intermittent. May be formed.

FIG. 3 is a cross-sectional view showing an enlarged inner surface shape of the first divided body 21 and the second divided body 22 according to the first embodiment. Specifically, FIG. 3 is an enlarged view of the dashed lines C1 and C2 in FIG.

As shown in FIG. 3, the inner surface shape of the first divided body 21 and the second divided body 22, that is, the inner surface shape forming the flow path 11 is formed by intermittently patterning a concave portion 19 having a rectangular shape in cross section. ing. Thereby, irregularities are continuously formed on the inner surface of the flow passage of the drain pipe 10. These irregularities constitute the texture 18 of the inner surface of the flow path. Note that the texture 18 shown in FIG. 3 is merely an example of a texture, and the shape and size of the texture may be any. In addition, the texture may be provided on the entire inner surface of the flow channel or may be provided partially. A texture suitable for controlling drainage flowing through the flow channel 11 may be employed.

[Mold]
Next, a mold for forming the drain pipe 10 will be described.

FIG. 4 is a cross-sectional view showing the mold according to the first embodiment, which is opened. FIG. 5 is a cross-sectional view of the mold according to the first embodiment, showing a state in which the mold is closed at the time of primary injection.

As shown in FIGS. 4 and 5, the mold 300 is provided in a molding machine (not shown) that performs die slide injection molding (DSI molding), and includes a first mold 400 and a second mold 500. Have. The first mold 400 and the second mold 500 are made of, for example, a metal material such as stainless steel.

The first mold 400 is a mold for molding a part of the first divided body 21 and a part of the second divided body 22. Specifically, the first mold 400 has a first cavity 410 for molding the outer shape of the first divided body 21 and a second cavity for molding the inner shape and the recess 223 of the second divided body 22. One core section 420 is provided. In the first cavity portion 410, a concave portion corresponding to the external shape of the first divided body 21 is formed. The first core portion 420 has a convex portion corresponding to the internal shape of the second divided body 22 and the concave portion 223.

２The second mold 500 is a mold for molding a part of the first divided body 21 and a part of the second divided body 22. Specifically, the second mold 500 has a second core portion 510 for forming the internal shape of the first split body 21 and the concave portion 213 and a second core portion 510 for forming the outer shape of the second split body 22. Two cavities 520 are provided. A concave portion corresponding to the external shape of the second divided body 22 is formed in the second cavity portion 520. The second core portion 510 has a convex portion corresponding to the internal shape of the first divided body 21 and the concave portion 213.

FIG. 6 is an enlarged cross-sectional view showing a region where the internal shape of the second divided body 22 is formed in the first core portion 420 according to the first embodiment. Note that FIG. 6 also illustrates the second divided body 22 formed by the first core portion 420.

テクスチャ As shown in FIG. 6, a texture forming section 425 for forming the texture of the inner surface of the flow path is formed in a region of the first core portion 420 where the internal shape of the second divided body 22 is formed. The texture forming section 425 has an uneven shape corresponding to the texture 18. That is, by forming a shape corresponding to the desired texture 18 in the texture forming section 425, the desired texture 18 can be formed on the inner surface of the flow path of the drain pipe 10 only by injection molding.

テクスチャ A similar texture forming portion 425 is also provided in a region of the first core portion 420 where the internal shape of the second divided body 22 is formed.

As shown in FIG. 5, when the first mold 400 and the second mold 500 are closed before the primary injection, the first cavity portion 410 and the second core portion 510 form the first divided body 21. The cavity (space) 210 is formed, and the second cavity portion 520 and the first core portion 420 form a cavity (space) 220 for the second divided body 22.

{Circle around (1)} In the first mold 400, a first molding gate 450 for injecting the resin material for primary injection into the cavity 220 is formed. The injection port of the first molding gate 450 is arranged in the first core portion 420 at a position corresponding to the concave portion 223 of the second divided body 22.

{Circle around (2)} In the second mold 500, a second molding gate 550 for injecting a resin material for primary injection into the cavity 210 is formed. The injection port of the second molding gate 550 is arranged in the second core portion 510 at a position corresponding to the concave portion 213 of the first divided body 21.

As described above, the first molding gate 450 and the second molding gate 550 are gates for primary injection, and their injection ports are arranged at positions corresponding to the joint portions 23 formed by the

recesses

213 and 223. ing.

{Circle around (2)} A joining gate 560 for injecting a resin material for secondary injection is formed in the second mold 500. The junction gate 560 is a gate for secondary injection. The exit of the joining gate 560 is arranged at a position corresponding to the rib 231 in the joining portion 23. Specifically, a plurality of junction gates 560 are provided so as to correspond to the ribs 231 formed in the

gaps

25 and 27 of the second divided body 22 (two are shown in FIG. 4 and the like).

The molding machine includes an injection molding section (not shown) for injecting a resin material into the first molding gate 450, the second molding gate 550, and the joining gate 560, and a first mold 400 and a second mold. A first drive source (not shown) for switching between closing and opening the mold 500, and a second drive source (not shown) for sliding the second mold 500 relative to the first mold 400 when the mold is opened. Are provided. The slide movement of the second mold 500 by the second drive source may be a straight movement or a rotational movement, but in the following description, the straight movement will be described as an example.

The molding machine further includes a computer (control circuit) for controlling the operation of each device such as the injection molding unit, the first drive source, and the second drive source. The computer includes, for example, a nonvolatile memory in which a program is stored, a volatile memory that is a temporary storage area for executing the program, an input / output port, and a processor that executes the program.

[motion]
Subsequently, a method for manufacturing a resin molded product according to the first embodiment will be described. In the description of this manufacturing method, the resin material before curing is shown by hatching.

The method of manufacturing a resin molded product is performed by a computer of a molding machine executing a program and controlling operations of respective devices such as an injection molding unit, a first drive source and a second drive source.

First, during standby, as shown in FIG. 4, the first mold 400 and the second mold 500 are open. Then, with the start of resin molding, the first mold 400 and the second mold 500 are closed as shown in FIG.

成形 After the mold is closed, the molding process is performed.

FIG. 7 is a cross-sectional view showing the state of the mold 300 during the molding step according to the first embodiment. In FIG. 7, the resin material before curing is shaded.

(7) As shown in FIG. 7, a resin material is primarily injected into the

cavities

210 and 220 from the first molding gate 450 and the second molding gate 550, respectively. Thereby, the first divided body 21 and the second divided body 22 are individually formed. At this time, a region corresponding to the second divided body 22 in the first mold 400 (first core part 420) and a region corresponding to the first divided body 21 in the second mold 500 (second core part 510) In addition, since the texture forming portion 425 is formed, the texture 18 is formed on the inner surface of the flow path of the first divided body 21 and the second divided body 22 (see FIG. 6).

移動 After the forming step, the moving step is performed.

FIG. 8 is a cross-sectional view showing the state of the mold 300 during the moving process according to the first embodiment.

After the molding process, when the first divided body 21 and the second divided body 22 are cured, the first mold 400 and the second mold 500 are once opened, and then the second mold 500 is moved to the first mold 500. It slides with respect to the mold 400. Then, as shown in FIG. 8, the first mold 400 and the second mold 500 are closed again. Between the time the mold is opened and the time the mold is closed again, the first divided body 21 is held in the first cavity 410 of the first mold 400, and the second divided body 520 is held in the second cavity 520 of the second mold 500. The two-piece body 22 is held. Then, by closing the mold, the joining edge 212 of the first divided body 21 and the joining edge 222 of the second divided body 22 come close to each other and abut each other.

At this time, a space S1 in which the secondary injection resin material is filled is formed between the first mold 400, the second mold 500, the first divided body 21 and the second divided body 22.

接合 After the moving step, a joining step is performed.

FIG. 9 is a cross-sectional view showing the state of the mold 300 during the joining step according to the first embodiment.

As shown in FIG. 9, in the joining step, a resin material is secondarily injected into the space S1 from the joining gate 560. When the entire space S1 is filled with the resin material, the joint 23 is formed. The joining portions 23 join the joining

edges

212 and 222 of the first split body 21 and the second split body 22 to each other. Note that the same resin material is used for the primary injection and the secondary injection. Examples of the resin material used in the primary injection and the secondary injection include thermoplastic materials such as PP (polypropylene) and ABS resin.

Then, after the joining step, when the joining portion 23 is cured, the first mold 400 and the second mold 500 are opened, and the drain pipe 10 shown in FIGS. 1 and 2 is taken out.

Before the resin material is secondarily injected into the space S1, the surface of the portion of the first divided body 21 and the second divided body 22 where the joint 23 is to be formed is subjected to surface modification such as plasma processing. Quality treatment may be performed. Thereby, minute irregularities are formed on the surface. The unevenness exerts an anchor effect, and the bonding strength between the second injected resin material and the first divided body 21 and the second divided body 22 can be improved.

(Second embodiment)
Next, a drain pipe according to a second embodiment will be described with reference to FIGS.

FIG. 10 is a sectional view of a drain pipe according to the second embodiment. Specifically, FIG. 10 is a diagram corresponding to FIG. In the following description, the same parts as those of the drain pipe 10 according to the first embodiment are denoted by the same reference numerals, and description thereof may be omitted.

As shown in FIG. 10, in the first divided body 21A and the second divided body 22A forming the drain pipe 10A, outer walls forming the flow path 11 (see FIG. 1) are formed without gaps. The first divided body 21A is provided with a wall portion 291 for separating the first straight portion 111 and the second straight portion 112, and a wall portion 292 for separating the second straight portion 112 and the third straight portion 113. ing. Similarly, in the second divided body 22A, a wall portion 293 separating the first straight portion 111 and the second straight portion 112, a wall portion 294 separating the second straight portion 112 and the third straight portion 113, Is provided.

In the cross-sectional view, the

walls

291 and 292 of the first divided body 21A are formed lower than the

walls

293 and 294 of the second divided body 22A. Then, the wall portion 291 of the first split body 21A and the wall portion 293 of the second split body 22A are abutted, and are joined by filling the filling portion 298 with a resin material for secondary injection. Also, the wall portion 292 of the first divided body 21A and the wall portion 294 of the second divided body 22A are abutted, and are joined by filling the filling portion with a resin material for secondary injection. Thereby, the joining position P of the

wall portions

291, 292, 293, and 294 is a position biased outward of the first divided body 21A.

接合 Joint projections

281 and 282 projecting outward are formed on the outer peripheral edge of the first divided body 21A and the second divided body 22A except for the inflow port 12 and the outflow port 13. By joining the joining

protrusions

281 and 282, the outer peripheral edges of the first divided body 21A and the second divided body 22A are integrated.

When the first divided body 21A is molded, a primary injection gate may be provided at a position corresponding to at least one of the end surfaces of the

walls

291 and 292 of the first divided body 21A. On the other hand, at the time of molding the second divided body 22A, it is preferable that a gate for primary injection is provided at a position corresponding to at least one end face of the

walls

293 and 294 of the second divided body 22A. An arrow G1 in FIG. 10 illustrates a gate position for primary injection of the first divided body 21A, and an arrow G2 illustrates a gate position for primary injection of the second divided body 22A. The mold may be manufactured so that each gate is arranged at such a position.

FIG. 11 is an enlarged sectional view showing a part of the drainage pipe 10A before the secondary injection according to the second embodiment in an enlarged manner. Specifically, FIG. 11 shows a contact state between the wall portion 291 of the first divided body 21A and the wall portion 293 of the second divided body 22A, which is surrounded by the alternate long and short dash line L1 in FIG. Note that the wall 292 of the first divided body 21A and the wall 294 of the second divided body 22A have the same structure, and a description thereof will be omitted.

As shown in FIG. 11, the boundary between the wall portion 291 of the first divided body 21A and the wall portion 293 of the second divided body 22A is filled with a space having a circular shape in a sectional view over the entire length of the

wall portions

291 and 293. A part 298 is formed. At least one gate portion 299 penetrating to the filling portion 298 is formed in the first divided body 21A. By filling the filling portion 298 with the resin material for secondary injection via the gate portion 299, the wall portion 291 of the first divided body 21A and the wall portion 293 of the second divided body 22A are joined. . Here, as described above, since the joining position P of the

wall portions

291 and 293 is a position biased to the outside of the first divided body 21A, the total length of the gate portion 299 can be shortened. Therefore, even if the resin material passes through the gate portion 299, the resin material can be filled in the filling portion 298 in a state of high fluidity without cooling.

FIG. 12 is an enlarged sectional view showing a part of the drainage pipe 10A before the secondary injection according to the second embodiment in an enlarged manner. Specifically, FIG. 12 shows an enlarged portion surrounded by a dashed line L2 in FIG.

As shown in FIG. 12, the boundary between the joint protrusion 281 of the first divided body 21A and the joint protrusion 282 of the second divided body 22A is a space having a circular cross section over the entire length of the

joint protrusions

281 and 282. A filling portion 288 is formed. At the boundary between the joint protrusion 281 and the joint protrusion 282, at least one gate portion 289 penetrating to the filling portion 288 is formed. By filling the filling portion 288 with the resin material for secondary injection via the gate portion 289, the joining

protrusions

281 and 282 are joined to each other.

嵌合 Furthermore, a fitting portion 285 is formed at the boundary between the joining protrusion 281 and the joining protrusion 282, on the side of the flow path 11 from the filling portion 288. The fitting portion 285 includes a convex portion 285a formed on one of the first divided body 21A and the second divided body 22A, and a concave portion 285b formed on the other. FIG. 12 illustrates a case where the convex portion 285a is formed on the second divided body 22A and the concave portion 285b is formed on the first divided body 21A, but these may be reversed. The fitting portion 285 is formed continuously along the entire length of the filling portion 288. Even if the resin material attempts to enter the flow channel 11 from the filling portion 288, the fitting portion 285 blocks it.

(Third embodiment)
Next, a drain pipe according to a third embodiment will be described with reference to FIGS.

FIG. 13 is a cross-sectional view of a state where the first divided body and the second divided body of the drain pipe according to the third embodiment are divided, and FIG. 14 is a state after the drain pipe moving step according to the third embodiment. FIG. 3 is a cross-sectional view before a bonding step. Specifically, FIG. 14 is a diagram corresponding to FIG. 10 in the second embodiment. In addition, in the following description, the same code | symbol is attached | subjected to the part equivalent to the drainage pipe 10A which concerns on 2nd embodiment, and the description may be abbreviate | omitted.

As shown in FIG. 13, in the first divided body 21B and the second divided body 22B forming the drain pipe 10B, outer walls forming the flow path 11 (see FIG. 1) are formed without gaps. The second divided body 22B is provided between the first straight portion 111 and the second straight portion 112 and between the second straight portion 112 and the third straight portion 113, and is a wall portion that separates the two. 295, 295 are provided.

Although not particularly shown, the

joint protrusions

281 and 282, the filling part 288, the gate part 289, and the fitting part 285 (the convex part 285a and the concave part 285b) provided in the second embodiment are similarly provided on the drain pipe 10B. Can be

凹部 A concave portion 296 is formed in the first divided body 21B as a joining edge. The second divided body 22B is provided with a joining protrusion 2950 inserted into the concave portion 296 as a joining edge. The joining protrusion 2950 is formed by the tip of the wall 295.

成形 At the time of molding the first divided body 21B, it is preferable to provide a gate for primary injection on the inner wall surface of the concave portion 296 of the first divided body 21B. On the other hand, at the time of molding the second divided body 22B, a primary injection gate is preferably provided at a position corresponding to at least one end face of the

wall portions

295 and 295 of the second divided body 22B, The mold may be manufactured so that each gate is arranged at such a position.

FIG. 15 is an enlarged cross-sectional view showing a part of FIG. 14 showing the drain pipe 10B before the secondary injection according to the third embodiment.

よう As shown in FIG. 15, the joining projection 2950 of the second divided body 22B is inserted into the concave portion 296 of the first divided body 21B and closed by the moving step. The remaining space in the concave portion 296 into which the joining protrusion 2950 is inserted becomes a filling portion of the resin material for secondary injection. At least one gate portion (not shown) penetrating to the filling portion is formed in the first divided body 21B. The resin material for secondary injection is injected into the filling portion through the gate portion.

では In the third embodiment, a rib 2951 is provided at an end of the joining projection 2950 that contacts the recess 296. In the joining step, the resin material for secondary injection is injected through the gate portion, and as shown in FIG. 16, the resin material 297 for secondary injection is filled in the filling portion, thereby forming the first divided body. The recess 296 of 21B and the joining projection 2950 of the second divided body 22B are joined. At this time, since the joining protrusion 2950 has the rib 2951, the resin material 297 is prevented from protruding from the filling portion.

That is, in the case where the joining protrusion 2950 does not have the rib 2951, as shown in FIG. 17, when the filling portion is filled with the resin material 297 for secondary injection, the pressure of the resin material 297 causes a gap between the inner wall surfaces of the concave portion 296. As a result, a gap is formed between the inner wall surface of the concave portion 296 and the outer surface of the joint protrusion 2950, and the resin material 297 passes through the gap and excess resin material 2971 protrudes from the concave portion 296.

On the other hand, in the third embodiment, the filling portion is filled with the resin material 297 for secondary injection, and due to the pressure of the resin material 297, the force between the inner wall surfaces of the concave portions 296 and the force between the ribs 2951 are also applied. . For this reason, a gap is not easily formed between the inner wall surface of the concave portion 296 and the outer surface of the joining protrusion 2950, and the resin material 297 is hard to protrude from the concave portion 296.

(Fourth embodiment)
Next, a drain pipe according to a fourth embodiment will be described with reference to FIG.

The guide rib 181 as the texture 18 is provided at the end (i.e., the upper end) of the inner wall surface adjacent to the second straight portion 112 on the second bent portion 115 side of the inner wall surface of the third straight portion 113. . The leading end of the guide rib 181 protrudes downward from the upper end of the inner wall surface of the third linear portion 113 adjacent to the second linear portion 112.

(4) When the inside of the drain pipe 10 is filled with water, the oil and fat contained in the water hardly adheres to the inner wall surface. However, when the inside of the drain pipe 10 is not filled with water, fats and oils contained in water flowing along the inner wall surface tend to adhere to the inner wall surface. However, even in such a case, when the guide rib 181 is provided, it is difficult for water to be transmitted to the inner wall surface of the third straight portion 113 adjacent to the second straight portion 112. For this reason, by providing the guide rib 181, even when the inside of the drain pipe 10 is not filled with water, the oil and fat contained in the water is removed from the third straight portion 113 on the side adjacent to the second straight portion 112. Difficult to adhere to the inner wall.

突 Further, on the inner wall surface of the third straight portion 113, a ridge rib 182 as the texture 18 is formed. This makes it difficult for water to reach the inner wall surface of the third straight portion 113, as in the case of the guide rib 181, and even when the inside of the drain pipe 10 is not filled with water, the oil and fat contained in the water is applied to the inner wall surface. Difficult to adhere.

(Other)
As described above, the insert molding apparatus according to the present invention has been described based on the embodiments, but the present invention is not limited to the above embodiments.

For example, in the above-described embodiment, a resin material is secondarily injected into each of the joining

edges

212 and 222 of the first divided body 21 and the second divided body 22 in the joining step, so that the joining portion 23 is formed. The case where the joining

edges

212 and 222 are joined to each other by molding is illustrated. However, in the joining step, the joining

edges

212 and 222 of the first divided body 21 and the second divided body 22 may be thermally welded to each other to join the joining

edges

212 and 222 together. By employing a so-called HP-DSI (hot plate DSI) for the bonding step, secondary injection is not required, and the mold can be simplified.

In the above-described embodiment, gaps (

first gaps

24 and 25 and second gaps 26 and 27) are formed between the outer walls of the flow channel 11 that are opposed by the first bent portion 114 and the second bent portion 115. The illustrated drain pipe 10 has been described as an example. However, a drain pipe in which the outer walls are close to each other and have no gap may be used.

Further, in the above embodiment, the case where the resin material in the primary injection and the resin material in the secondary injection are the same is illustrated, but the resin material in the primary injection and the resin material in the secondary injection are It may be different. Thereby, the degree of freedom in selecting the resin material used in the primary injection or the secondary injection can be increased. In particular, it is also possible to individually select a resin material suitable for each characteristic of the primary injection and the secondary injection.

For example, in the secondary injection, since the resin material is poured into the space S1 having a smaller sectional area than the

cavities

210 and 220, the fluidity of the secondary injection resin material may be higher than that of the primary injection resin material. desired. In this case, a resin material having higher fluidity than the resin material for the primary injection may be used for the secondary injection. If the fluidity of the resin material for secondary injection is increased, the resin material can be supplied to the entire space S1 even if the number of the junction gates 560 is reduced.

添加 Also, additives can be added to the resin material. In order to improve the impact resistance, rubber, estramer, or the like may be added to the resin material. Further, in order to increase the bonding strength, a strength-specific grade material (filler) may be added to the resin material for secondary injection.

樹脂 Also, a resin material that does not easily adhere to oil, such as an acrylic resin, may be used.

In addition, a form obtained by applying various modifications conceived by those skilled in the art to each embodiment, and a form realized by arbitrarily combining the components and functions in each embodiment without departing from the spirit of the present invention are also included. Included in the present invention.

As is clear from the above-described first to third embodiments and the modifications thereof, the method of manufacturing a resin molded product according to the first aspect includes joining the first divided body 21 and the second divided body 22 together. This is a method for producing a resin molded product for molding the drain pipe 10 having the flow path 11. This manufacturing method includes a forming step, a moving step, and a joining step. In the molding step, a resin material is primarily injected into the

cavities

210 and 220 formed by the first mold 400 and the second mold 500, and the first divided body 21 and the second divided body 22 are individually molded. In the moving step, the first mold 400 holds the first divided body 21 and the second mold 500 holds the second divided body 22, and the first mold 400 and the second mold 500 are moved. By the relative movement, the respective joining

edges

212 and 222 of the first divided body 21 and the second divided body 22 are brought closer to each other. In the joining step, the joining

edges

212 and 222 of the first divided body 21 and the second divided body 22 are joined. At least one of the first core portion 420 of the first mold 400 and the second core portion 510 of the second mold 500 is provided with a texture forming portion 425 for forming the texture 18 on the inner surface of the flow path.

According to the first aspect, since the texture molding section 425 is provided on at least one of the first core section 420 of the first mold 400 and the second core section 510 of the second mold 500, the first When the divided body 21 and the second divided body 22 are formed by primary injection, the texture 18 can be formed at the same time. Therefore, the desired texture 18 can be reliably formed on the inner surface of the flow channel of the drain pipe 10 without executing a process dedicated to texture formation.

In addition to forming the texture 18 by the texture forming section 425, after joining the first divided body 21 and the second divided body 22, a plasma generating electrode is inserted into the inside thereof to perform a plasma treatment, and the surface is modified. The texture may be formed on the inner surfaces of the first divided body 21 and the second divided body 22 by texture.

では In the second aspect, the present invention is realized by a combination with the first aspect. In the second aspect, in the joining step, the resin material is secondarily injected into each of the joining

edges

212 and 222 of the first divided body 21 and the second divided body 22, thereby joining the joining

edges

212 and 222. They are joined together.

According to the second aspect, the desired texture 18 can be reliably formed even when the first divided body 21 and the second divided body 22 are integrated by injecting the resin material secondarily. .

では The third aspect is realized by a combination with the second aspect. In the third aspect, a concave portion 296 is formed on the first divided body 21 (21B) as the joining edge, and a joining projection 2950 is formed on the second divided body 22 (22B) as the joining edge. Then, the joining protrusion 2950 formed on the second divided body 22 is inserted halfway into the concave part 296 formed on the first divided body 21, and the resin material is secondarily injected into the remaining space of the concave part 296, The joining edges are joined to each other, and a rib 2951 is provided at an end of the joining projection 2950 that contacts the concave portion 296.

According to the third aspect, the pressure between the ribs 2951 as well as the force between the inner wall surfaces of the concave portion 296 is exerted by the pressure of the resin material 297. For this reason, a gap is not easily formed between the inner wall surface of the concave portion 296 and the outer surface of the joining protrusion 2950, and the resin material 297 is hard to protrude from the concave portion 296.

では In the fourth embodiment, the present invention is realized by a combination with the second or third embodiment. In the fourth embodiment, the resin material in the primary injection is the same as the resin material in the secondary injection.

According to the fourth aspect, since the same resin material is used for the primary injection and the secondary injection, the bonding strength between the first divided body 21 and the second divided body 22 and the bonding part 23 can be increased. it can. In addition, since the same resin material can be used, it is possible to use a common injection molding part for primary injection and secondary injection.

では In the fifth embodiment, the present invention is realized by a combination with the second or third embodiment. In the fourth embodiment, the resin material in the primary injection is different from the resin material in the secondary injection.

According to the fifth aspect, since different resin materials are used for the primary injection and the secondary injection, the degree of freedom in selecting a resin material used for the primary injection and the secondary injection can be increased.

では The sixth aspect is realized by a combination with the first to fifth aspects. In the sixth aspect, the resin molded product is a drain pipe 10 in which a hollow portion serves as a flow path 11. According to the sixth aspect, even when the drain pipe 10 is manufactured, the texture 18 can be reliably formed.

では The seventh aspect is realized by a combination with the sixth aspect. In the seventh aspect, the flow path 11 has at least one bent portion (first bent portion 114 and second bent portion 115) bent in a U-shape. According to the seventh aspect, the texture 18 can be reliably formed even when the drain pipe 10 having two bent portions such as an S-shaped trap is manufactured.

８ The eighth aspect is realized by a combination with the seventh aspect. In the eighth aspect, gaps (

first gaps

24 and 25 and second gaps 26 and 27) are formed between the outer walls of the flow path 11 that are opposed by the bent portion. According to the eighth aspect, the first molding gate 450, the second molding gate 550, and the joining gate 560 can be formed at locations corresponding to the gaps.

では The ninth aspect is realized by a combination with the eighth aspect. In the ninth aspect, the

first gaps

24, 25 and the

second gaps

26, 27 of the drain pipe 10 are formed with ribs 231 projecting from one of the outer walls toward the other. According to the ninth aspect, the rib 231 reinforces the drain pipe 10, and the rigidity can be increased.

１０The tenth aspect is realized by a combination with the ninth aspect. In the tenth aspect, the rib 231 is connected to the outer walls. According to the tenth aspect, since the rib 231 is connected to the outer walls, the rib 231 is bridged between the

first gaps

24 and 25 and the

second gaps

26 and 27. Therefore, the rigidity of the entire drainage pipe 10 can be further increased.

では The eleventh aspect is realized by a combination with the tenth aspect. In the eleventh aspect, the rib 231 is formed by secondary injection. According to the eleventh aspect, when the first divided body 21 and the second divided body 22 are integrated by secondary injection, the rib 231 can be formed at the same time.

１２The twelfth aspect is realized by a combination with the ninth to eleventh aspects. In the twelfth aspect, the first molding gate 450, which is the primary injection gate, and the second molding gate 550 are provided at positions corresponding to the ribs 231. According to the twelfth aspect, the second molding gate 550 can be arranged near the cavity 210 for the first divided body 21, and the first molding gate 550 can be arranged near the cavity 220 for the second divided body 22. 450 can be located. Therefore, the filling balance of the resin material into the

cavities

210 and 220 can be improved, and the first divided body 21 and the second divided body 22 can be formed uniformly.

１３ The thirteenth aspect is realized by a combination with the ninth to twelfth aspects. In the thirteenth aspect, the junction gate 560, which is a gate for secondary injection, is provided at a position corresponding to the rib 231. According to the thirteenth aspect, the filling balance at the time of forming the joint portion 23 can be improved, and the entire drain pipe 10 can be uniformly formed.

１４ The fourteenth aspect is realized by a combination with the first aspect. In a fourteenth aspect, in the joining step, the joining edges of the first divided body 21 and the second divided body 22 are joined by heat welding.

According to the fourteenth aspect, the secondary injection becomes unnecessary, and the mold 300 can be simplified.

DESCRIPTION OF SYMBOLS 10 Drainage pipe 11 Flow path 114 1st bending part 115 2nd bending part 18 Texture 21 1st divided body 21B 1st divided body 210 cavity 212 joining edge 22 2nd divided body 22B 2nd divided body 220 cavity 222 joining edge 231 rib 24 First gap 25 First gap 26 Second gap 27 Second gap 2950 Joining projection 2951 Rib 296 Concave section 400 First mold 420 First core section 425 Texture molding section 450 First molding gate 500 Second mold 510 2 core part 550 Second molding gate 560 Joining gate

Claims

A method of manufacturing a resin molded product by molding a resin molded product having a hollow portion by joining a first divided body and a second divided body,
A molding step of primarily injecting a resin material into a space formed by the first mold and the second mold to individually mold the first divided body and the second divided body;
While holding the first divided body in the first mold and holding the second divided body in the second mold, the first mold and the second mold are moved relative to each other. A moving step of bringing the joining edges of the first divided body and the second divided body closer to each other;
A joining step of joining respective joining edges of the first divided body and the second divided body,
In at least one of a region corresponding to the second divided body in the molding step in the first mold and a region corresponding to the first divided body in the molding step in the second mold, A method for producing a resin molded article, comprising a texture molding section for molding the texture of the inner surface of the resin molded article.
The said joining process WHEREIN: A resin material is secondary-injected with respect to each said joining edge of the said 1st divided body and the said 2nd divided body, and the said joining edge is joined. Production method of resin molded products.
A recess is formed in the first divided body as the joining edge,
A joining projection is formed on the second divided body as the joining edge,
In the joining step, the joining projection formed on the second divided body is inserted halfway into the recess formed on the first divided body, and the resin material is secondarily injected into the remaining space of the recess. Thereby, the joining edges are joined to each other,
The method for manufacturing a resin molded product according to claim 2, further comprising a rib at an end portion of the joining protrusion that contacts the concave portion.
The method of manufacturing a resin molded product according to claim 2, wherein a resin material in the primary injection is the same as a resin material in the secondary injection.
The method for manufacturing a resin molded product according to claim 2, wherein a resin material used in the primary injection is different from a resin material used in the secondary injection.
The method for producing a resin molded product according to any one of claims 1 to 5, wherein the resin molded product is a drain pipe in which the hollow portion serves as a flow path.
The method according to claim 6, wherein the flow path has at least one bent portion bent in a U-shape.
The method for manufacturing a resin molded product according to claim 7, wherein a gap is formed between outer walls of the flow path that are opposed by the bent portion.
The method according to claim 8, wherein a rib protruding from one of the outer walls toward the other is formed in the gap of the drain pipe.
The method according to claim 9, wherein the rib is connected to the outer walls.
The method for manufacturing a resin molded product according to claim 10, wherein the rib is formed by the secondary injection.
The method for producing a resin molded product according to any one of claims 9 to 11, wherein the gate for primary injection is provided at a position corresponding to the rib.
The method for manufacturing a resin molded product according to any one of claims 9 to 12, wherein the secondary injection gate is provided at a position corresponding to the rib.
The method for manufacturing a resin molded product according to claim 1, wherein in the joining step, the joining edges are joined by thermally welding the joining edges of the first divided body and the second divided body. .